Conventional or commercial continuous vertical casting operations are capable of casting either a single bar or a pair of bars.
As the bars are cast through a mold or die, the bars are drawn downwardly through opposed pinch rolls which engage opposite side portions of the bar, with the pinch rolls rotating about horizontal axes. In many installations, it is conventional to use upper and lower sets of pinch roll assemblies to draw the cast bar downwardly along a predetermined vertical path.
Single bar casting operations are often utilized for larger size bars (for example, up to ten inches in diameter) since there is insufficient room when utilizing conventional size crucibles, for accommodating two relatively large size bars. Although smaller size bars (up to three inches in diameter) may be cast in tandem ("double bar" or "twin strand" casting) utilizing conventional size crucibles, it is necessary to prolong stoppage of the casting operation in order to change crucibles or change or adjust pinch rolls when converting from a single bar casting operation to a double bar casting operation or vice versa. In addition, adjustment of the pinch rolls can become even more time consuming when it is necessary to relocate the pinch rolls in each assembly for casting along different casting lines, depending on the size of the crucible, in a double bar casting operation. The casting line is the vertical axis along which the bar is cast. Due to size limitations of two types of crucibles (round or flat bottom crucibles) commonly used in industry, the bars in double bar casting operations, must be cast along five or six inch spaced casting lines depending on the type of crucible used.